Recently, wind turbines have received increased attention as environmentally safe and relatively inexpensive alternative energy sources. With this growing interest, considerable efforts have been made to develop wind turbines that are reliable and efficient.
Generally, a wind turbine includes a rotor having multiple blades. The blades are attached to a rotatable hub on the rotor. The blades transform mechanical wind energy into a mechanical rotational torque that drives one or more generators. The generators are generally, but not always, rotationally coupled to the rotor through a gearbox. The gearbox steps up the low rotational speed of the turbine rotor for the generator to efficiently convert the rotational mechanical energy to electrical energy, which is fed into a utility electric power grid. The rotor, generator, gearbox and other components are typically mounted on a heavy bedframe with a housing, or nacelle, that is positioned on top of a tower that may be a truss or tubular tower.
The nacelle structure is generally formed of a cast or otherwise solid fabricated metal housing bedframe or bedplate, which introduces substantial weight a the top of the wind turbine tower. Furthermore, the heavy bedplate-nacelle structure includes load support features to support internal drive train components within the nacelle. The load support features add additional weight to the nacelle structure and the drivetrain component housings. Additionally, load support features may not effectively transfer loads and stresses within the bedplate-nacelle housing to be transferred to the tower, and also may introduce unwanted loads and stresses to the drivetrain components themselves. The increased weight increases capital costs, logistics, and operational cost of the wind turbine. Today's state-of-the-art wind turbines use a heavy bedframe design and the nacelle. The nacelle is a non-load bearing enclosure used primarily to keep the weather from directly impacting the individual components of the drivetrain.
What is needed is a highly integrated spaceframe and compact drivetrain that replaces the bedplate-nacelle structure, which reduces weight and efficiently transfers rotor operational loads, drivetrain torque and weight to the tower.